In a chemical reaction process such as organic synthesis or crystallization, a reaction liquid is required to be retained at a prescribed temperature. Therefore, a double structure jacket type container is used in which a jacket is provided on the outer side of a reaction vessel and a heat transfer medium can be circulated between the jacket and the reaction vessel. A heat transfer medium having a prescribed temperature is provided in the jacket, and the reaction liquid in the reaction vessel has been adjusted at a prescribed temperature (see, for example, Patent Document 1).